Search: id:A120617 Results 1-1 of 1 results found. %I A120617 %S A120617 1,2,4,8,16,32,64,128,256,512,1024,2048,4096,8192,16384,32768,65536,131072, %T A120617 262144,524288,1048576,2097152,4194304,8388608,16777216,33554432,67108864, %U A120617 134217728,268435456,536870912,1073741824,2147483648,4294967296,8589934592 %V A120617 1,-2,-4,8,16,-32,-64,128,256,-512,-1024,2048,4096,-8192,-16384,32768, 65536,-131072, %W A120617 -262144,524288,1048576,-2097152,-4194304,8388608,16777216,-33554432,-67108864, %X A120617 134217728,268435456,-536870912,-1073741824,2147483648,4294967296,-8589934592 %N A120617 Hankel transform of g.f. 1/sqrt(1+4x^2). %C A120617 Hankel transform of e.g.f. Bessel_I(0,2*sqrt(-1)*x) or (1,0,-2,0,6,0, -20,...). Hankel transform of sum{k=0..n, (-1)^(n-k)*C(n,k)^2}. Hankel transform of A098331. %C A120617 Hankel transform of A082590. [From Paul Barry (pbarry(AT)wit.ie), Apr 26 2009] %F A120617 G.f.: (1-2x)/(1+4x^2); a(n)=2^n*(cos(pi*(n+1)/2)+sin(pi*(n+1)/2)) %Y A120617 Sequence in context: A084633 A122803 A000079 this_sequence A050732 A138815 A103662 %Y A120617 Adjacent sequences: A120614 A120615 A120616 this_sequence A120618 A120619 A120620 %K A120617 easy,sign %O A120617 0,2 %A A120617 Paul Barry (pbarry(AT)wit.ie), Jun 17 2006 Search completed in 0.001 seconds